Pleasure and pain with Michael Mosley.

Mosley tries to unravel the science behind our reward system and to assess the difference between pleasure and pain. Mosley, fulfilling his typical desire for self-experimentation, takes a bungee jump, joins in with a hot chilli eating competition, has his legs waxed and stands in ice cold water. Johanna has restless genital syndrome (REGS) which means that she is on the verge of an orgasm 24 hours a day. A couple and their guests have their oxytocin levels measured on their wedding day, before and after the ceremony in order to prove the chemistry of love. Samson Parker describes how he had to amputate his own arm with a pen knife following a farming accident which meant he had to switch off the feelings of pain. Ashleyn has congenital insensitivity to pain (CIP), a genetic condition which means she cannot feel any pain.